In Defense of the Electric Car – part 3

Full disclosure: I own an electric car, and I think they are useful for city transportation. However, having owned one for a decade, I can say that it hasn’t been practical or cost-effective. John Hardy believes they are the future, I’ll let you, the reader, decide. – Anthony Watts

Part 1 of this series expressed the view that regardless of “the environment”, EVs are poised to inflict a massive disruption on the automotive industry, and outlined the strengths of the technology and some of the reasons that it is happening now.

Part 2 discussed the main issues for Western automakers in handling this disruption

Part 3 below is devoted to common misconceptions which cause some to mistakenly conclude that EVs will not be practicable in the foreseeable future.

The demise of the Western auto industry: Part 3 – common misconceptions

Misconception 1: batteries will never get us to acceptable range.

The combination of a 300 mile range and fast charge should be plenty. How many people routinely drive more than 300 miles without stopping for toilet and/or food? For most people, most of the time averaging 20 – 30 miles per day [1], charging could be done once a week. “Fast charge” needs to be fast however: 20 minutes from empty to 80% charge. The batteries are well able to handle this. The infrastructure uses well-understood technology (300+ Kw charging stations already exist in Beijing for buses [2]). Several current production EVs have a range of over 200 miles and some over 300.

With an average daily mileage for private cars of 20-30 miles per day and 3-4 miles per kW-hr the average charge needed is 5 to 10 kW-hr a day, equivalent to running a 7 kW electric shower for 40 to 80 minutes or warming up a few storage heaters over 5-6 hours.

Another mistaken assumption is that everyone will come home and charge at peak time in the early evening. Once again this is highly unlikely to become a problem. Incentivising people to charge off peak is trivial, as is the technology. I have my car set to start charging at 1:00 a.m. when my electricity price almost halves.

Misconception 3: EV charging will require rewiring all the houses in the land.

UK standard sockets handle almost 3 kW. Recharging an average day’s driving just from a wall socket might take 2 – 4 hours. Electric showers may run over 10kW, so adding a 10kW EV wall box is no more complex than installing an electric shower and would recharge an exhausted battery in a 300 mile range car in 7-10 hours.

Misconception 4: Generating capacity will be insufficient

It is sometimes said that if EVs take off, a huge increase in generating capacity will be needed. In the UK there were some scary (and ill-informed) press comments on a document published recently by the National Grid entitled Future Energy Scenarios (FES). The National Grid looked at four different scenarios. One of them concluded that additional demand resulting from an all-EV world would be about 5 Gw. On the face of it, this doesn’t seem to compute: to recharge an EV like the Chevy Bolt or the Tesla Model 3 takes about 75 kW-hrs. 5 Gw over 24 hours is 120 Gw hrs or 120 million Kw-hrs, so 5 Gw extra sounds like it would cope with maybe 1 – 2 million EVs rather than the 30 million or so that would be on UK roads today if all our piston-engined cars became EVs overnight.

There are two factors at work here. Firstly as discussed earlier, EVs used as private cars need an average 5-10 Kw-hr per vehicle per day, so 120 Gw-hr would in theory support a population of 12 million vehicles.

There is another critical issue though: exploiting the variability of demand. Let us do some mental experiments:

Figure 1 is a graph of UK power requirements on a typical working day in winter. (The pattern and the numerical values will be different in Australia or the USA, but the principle is the same). The area under the line (the blue area in Figure 1) is the total electrical energy required during the 24 hours – 965 Gw-hrs in this example. Note that the power requirement varies greatly from a low around 30000 Mw (30 Gw) in the early hours of the morning to almost 50 Gw at 6:00 in the evening.

If the system was capable of sustaining 50 Gw for 24 hours, an additional 230 Gw-hrs could be generated (Figure 2):

Figure 2 Demand and (theoretical) spare capacity

230 Gw-hrs is 230,000,000 kw-hrs. Recall that to recharge an EV that has covered the UK average daily private car mileage, 5 – 10 Kw-hours are needed. So if we could put all the available 230 Gw-hrs into EV batteries we could, crudely and theoretically, service a population of between 32 million and 46 million EVs without any additional capacity. At the end of March 2017 there were around ~37 million vehicles licensed in Great Britain, of which ~31 million were cars [3]

Of course this analysis is simplified. It ignores a myriad of variables such as pumped storage, power imported from other countries, battery powered trucks, capacity currently used to refine and distribute petrol and so on, but as an order-of magnitude approximation it is useful.

Is it possible to manage demand like this? Certainly it is. All that is required is to give the control of “normal” charge rate to centralised automated processes (with appropriate over rides, agreed contractual arrangements and financial incentives). The technology to achieve this is straightforward.

But there is an even simpler way: between midnight and 7:00 a.m. the cumulative “energy available” is about 133 Gw-hrs: sufficient (theoretically) to do an average day’s charge on between 18 million and 26 million EVs. My electricity almost halves in price during those hours and my EV is capable of starting to charge at any time I wish; so I do most of my charging in those hours (Figure 3).

Figure 3 Overnight charging window midnight to 7:00 a.m.

There is another consideration here. One of the juggling acts that the controllers of any grid system must manage is spikes and troughs in demand. Electricity must in general be consumed as it is generated: so a sudden change in demand may require the start-up of additional generating capacity, the use of pumped storage, reducing supply to a flexible consumer, additional imports etc. If they do it right, voltage and frequency stay steady and nobody notices. If they get it slightly wrong we have temporary brownouts. If they make a complete mess of things, or are hit by too many variables at once the system can collapse as happened recently in South Australia.

Figure 4 is an example of just such a peak. It is half time in a televised football (soccer) match. Within a minute or so the demand goes up by around 1 Gw. This is about the total output of the Sizewell B nuclear power plant, or a quarter of the capacity of the Drax power station – largest in the UK.

Figure 4 Example of spike in demand with a “normal” day for comparison

Wind energy complicates this juggling act because the output of a wind turbine is intrinsically variable and can change extremely rapidly. A sudden storm hitting a wind farm such as the London Array (630 Mw) could take ½ Gw off line in seconds. With the right technology and the right contractual arrangements between householders and the energy companies, 30 million EVs provide a powerful and flexible tool for the unseen (and under-valued) grid jugglers.

Time for another thought experiment.

Suppose our 30 million EVs had a battery capacity of 75 kW-hrs (similar to today’s Chevy Bolt and entry level Tesla Model 3). Suppose the contractual deal was that the grid managers could help themselves to (say) 10% of that capacity any time the vehicle was plugged in, provided that it was fully charged by a specified time. That would theoretically provide a 200+ Gw-hr buffer which could be dialled up and down almost instantly. In practice of course it would be less (not all the EVs would be plugged in and some would be less than 90% charged), but even (say) 50 Gw-hrs would be handy: it far exceeds the UK’s current pumped storage capacity for example.

[As an aside, whilst this sort of buffer would be very helpful in managing short-term peaks and troughs, the idea of 100% wind/solar with battery back-up for days or weeks is infeasible with current technology in the foreseeable future. Vey roughly UK demand in winter is around 1000 Gw-hr/day. If the sun didn’t shine and the wind didn’t blow for ten days, the UK alone would need ~10,000 Gw-hr of battery storage. That is 4-5 times the total battery capacity of a fleet of 30 million electric cars, and more than 300 times the total world output of lithium ion batteries in 2014]

Misconception #5: EVs will be constrained by a shortage of lithium

There is not enough lead around to power a large fleet of EVs, but there is almost certainly enough lithium.

Two factors in particular help

Lithium is not like oil. Oil is dug up, refined, distributed and burned. The supply requirements are ongoing. By contrast, lithium is extracted, made into batteries and, er that’s it for ten years or so. It is then (at least partially) recycled. Once lithium is in the system it will (mostly) stay there.

Lithium is not like lead. Very roughly, 60% of the weight of a lead acid battery is lead [4] and the energy density of a lead acid battery is about 30 watt-hours per kg; so a 75 Kw-hr lead acid battery (Chevy Bolt size) would weigh about 2,500 kg, of which 1,500 kg would be lead (that explains why lead acid EVs are experiments, not serious transport). Estimates of the amount of lithium used in a lithium ion battery vary greatly from about 80 grams per Kw-hr to 250 grams per Kw-hr [5]. These figures translate to a lithium content of between 6 and 19 kg of lithium for our hypothetical 75 Kw-hr battery. Either way there is about two orders of magnitude difference between the weight of lead and the weight of lithium used to produce a battery of the same capacity.

The US Geological Survey (USGS) suggests that “reserves” of lithium globally are about 14 million tons (this is measured as mass of an equivalent amount of pure lithium), but suggests a “Resources” figure of about 40 million tons [6]. At 13kg per car, 1 million tons of lithium would be sufficient for 76 million cars. One estimate is that global car production in 2016 was ~72 million [7]. If we assume the “worst case” of:

No lithium recycling (there are plants already up and running, but let’s be devil’s advocate and assume this)

Only 25% of reserves available for cars (the rest going into ceramics, commercial vehicles, grid storage etc)

No substitution of lithium by other metals in batteries

Only the USGS “reserve” of 14 million turned out to be available (i.e. the 40 million “resources” never materialise)

No substantial increase in efficiency of usage (i.e. Kw-hrs per kg of lithium remains unchanged)

If we make all these assumptions we can make the case that there is only enough lithium to support 3 or 4 years of car production in a world where all cars are electric. This is however a false picture for several reasons:

· The price of a finished battery is very insensitive to the price of the lithium raw material. This means that the price for lithium can increase greatly without having a noticeable effect on battery prices. This gives lots of financial headroom for exploiting reserves that are not economic at current prices. If the price goes high enough, it would in theory be possible to extract it from seawater. One estimate put the amount of lithium in the world’s oceans at 230 billion tons [8]

Over the years, reserves of oil have gone up very greatly (see for example [9]). It is not unreasonable to expect lithium reserves to increase in a similar way

As hinted earlier, lithium is in fact reclaimed from old batteries. Again, if shortages develop there is financial headroom to increase the efficiency of this process

Lithium is used in the battery cathode because it is the “best” element electrically. If shortages developed alternatives could be used (see for example [10])

Misconception #6 – No I’ll stop here

There are dozens of arguments fielded against EVs; I have yet to encounter one which stood up under examination. It is going to happen regardless of “the environment”; and if the Western manufacturers can’t or won’t adapt, the economic outlook for the rising generation does not look good.